Device and system for reflective digital light processing (DLP)

ABSTRACT

Aspects of the present invention include systems for reflective digital light processing (DLP). Embodiments include a light source, a plurality of optically reflective switching devices each having an optically reflective layer in contact with a substrate; a circuit means and power source; controller logic; a projection means; and a display means; wherein each of said plurality of devices is a capable of receiving light from said light source and thereafter reflecting said received light in direct response to a reflective state condition of said each device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of and claims priority fromU.S. patent application Ser. No. 13/164,174, filed Jun. 20, 2011.

FIELD OF INVENTION

The present invention generally relates to the field of display devicesand more particularly for optically reflective switching devices indisplay systems having very high resolution images such as reflectivelight valve arrays.

BACKGROUND OF THE INVENTION

Digital Light Processing (DLP) is a technology used in projectors andvideo projectors. In DLP applications such as image transmission systemsand projectors, a DLP image is created by microscopically small mirrorsthat are positioned and arranged in a matrix on a semiconductor chip.The “chip” is often referred to as a Digital Micromirror Device (DMD)and is used hereinafter a “chip” or “DMD chip”. Each micromirror, or asused herein “mirror,” on the chip typically represents one pixel in theprojected image.

FIG. 1 is a pictorial representation of a mirror 100 in a typical mirrorarray on a DMD. From FIG. 1, mirror 100 is positioned in proximity toother mirrors 110, 120, 130, 140 and 150 in which there exists a gapbetween the placement of each mirror at 111, 121, 131, 141, 151, as wellas at 161. These gap areas do not reflect light as instead they arerequired to exist in order to permit the mirrors to angle and repositionduring operation. Typically, a support post 170 of each mirror is incontact with a torsion hinge or other mechanical apparatus below themirror (not shown) to provide the capability of the mirror's movement.

FIG. 2 is a pictorial representation of a larger portion 200 of themirror array of FIG. 1. A DMD chip typically contains a rectangulararray of up to 2 million hinge-mounted mirrors where each of thesemirrors is of a dimension less than 20 microns or one-fifth the width ofa human hair.

FIG. 3 represents a pictorial representation of the underside of amirror 300 having a diagonal hinge 310.

FIG. 4 is a cut-away pictorial representation of a mirror on a chip 400.From FIG. 4, mirror 410 is supported by a mirror support post 420, whichis balanced on a yoke 430 that is midpoint a hinge assembly 440. As partof the hinge assembly 440, there are two hinge support posts 450 whichreside upon metal contact surface 460 above the substrate 470 of thechip 400.

FIG. 5 represents a schematic of a typical DLP system 500. In a typicalDLP system a light source 510, a color wheel 520, a chip 530 withassociated processor logic (such as but not limited a command logic)540, and a projection means such as a projection lens 550. From FIG. 5,as the white light source of 510 passes through the color wheel 520, acolored light is reflected from a mirror of the chip 530 in apredetermined manner based on its predetermined mechanical angleposition as being ON or OFF, and a resulting colored light is projectedthrough the lens 550 for viewing. In a DLP system, the mirrors on thechip may reflect an all-digital image onto a screen or other projectionsurface for a viewer's use.

Optically, pixels resulting from the projection, and their associatedresolution, are observable by the user's eye. For instance, in FIG. 6, atraditional projection DLP display system is shown 600. From FIG. 6, thesystem comprises a light source 610, a color wheel 620, a mirror array630 having, a projection lens 640 and a display screen 650. The lightsource 610 when emitted after passing though the color wheel 620 isreceived by a mirror on the array 630. The mirror on the array 630receiving the colored light is then switched to be ON or OFF inaccordance with the desired result, as predetermined, and the resultingcolor in relation to its angle is displayed on the display screen 650 atthat moment. Thereafter, the position of the mirror is again altered andan associated color is then displayed. This process repeats itselfthousands of times per second per mirror.

A DLP system will typically vary in the number of mirrors that arepresent on its respective chip, in view of the resolution sought for aparticular system. For instance, the number of mirrors directly affectsand corresponds to the resolution of the projected image, such thatimproved resolution characteristics require a greater number of properlypositioned and aligned mirrors on the chip. Typically, resolutions arerecognized as 800×600, 1024×768, 1280×720, etc., where resolutions suchas 1920×1080 and greater correspond with improved visual sensitivitiessuch as High Definition Television (HDTV). The placement and alignmentof the mirrors on the DMD is critical such that the mirrors may bepositioned so as to be capable of being repositioned rapidly to reflectlight either through the lens, imagery device or a heatsink.

In a DLP system, the mirrors on the chip are often mounted on miniaturemechanical hinges or yokes that provide tilting capability to eachmirror in relation to the light source of the system and the associatedelectrodes providing a charge. Typically, the mirrors on the DMD arerapidly repositioned thousands of times per second by one or moreelectrodes resident therewith from one position to another such that aseach mirror changes in angle by upwards of 20 degrees, the lightreflected off of the mirror is affected and the resulting reflectedlight, and its associated intensity, that then passes through a colorwheel of the system and eventually to the screen for viewing as a pixelis a direct result of the light reflected.

FIG. 7 is a pictorial representation of a typical mirror 710 undersidehaving two supports (720, 730) and two electrodes (740, 750). Where avoltage source providing current to each electrode acts to decreasevoltage applied to one electrode and/or acts to increases a voltageapplied to the other electrode, thereby creating an imbalance betweenthe electrostatic attraction generated between each electrode and themirror, resulting in the mirror to effectively tilt.

In a grayscale image system, where there is no color wheel, reflectedlight is white, black or a shade of grey, depending on the angle of themirror. For instance, when a mirror is angled in an “ON” position toreflect light, the resulting light reflected is one of white or a shadeof gray. Contradistinctively, when a mirror is angled in an “OFF”position to not reflect light, the result is no light reflected soeffectively no light, or black, is passed. Due to the speed ofadjustment, visually, when a mirror is switched on more than off, itresults in a reflection of a lighter-shade gray pixel, whereas when amirror is switched on more than off, it results in a reflection of adarker-shade gray pixel. The mirrors are adjusted in relation tocommands received from bit-streamed image code of the associated controlmodule resulting in mirrors that may adjust several thousand times persecond.

Generally, the movement of the mirrors in a display system includes theuse of electrodes, hinges, electrostatic attraction, piezoelectricdevice, and thermal actuators.

In a color DLP system, the projected white light of the light source,commonly generated by a lamp, typically first traverses through a colorwheel positioned prior to the chip. The color wheel filters theprojected light into its color scheme, which is often at least red,green, and blue, from which a single-chip DLP projection system is knownto create at least 16.7 million colors and a three-chip DLP projectionsystem is known to be capable of producing in excess of 35 trillioncolors. Reflected light from the mirrors of the chip is then passed forprojection onto a viewing surface where, for example, the color orange(or orange hue) results from a viewer's eye observing red and yellowlight simultaneously as a result of rapidly alternating flashes.

As can be appreciated reliable, economical and efficient techniques forhaving reliable DLP techniques are increasingly of interest particularlygiven cases where mirrors have become stuck in one position duringoperation, obvious limits in DLP technology requiring continuousrepositioning and precise alignment of mirrors resulting in requiredgaps between mirror surfaces which do not reflect light, dimensionallimitations of mirrors in traditional DLP systems with the resultinginherent limit to improved pixel resolution, and the continuous desireby users to have improved viewing and operational longevity in theirprojection systems.

Unfortunately, mirrors have become immovable in certain instances,particularly where capillary water condensation has occurred or wherevan der Waals forces have resulted. Additionally, as a matrix array ofmirrors is not continuous for reflectivity of projected light sources,gaps between mirrors also represent projection gaps in a viewer'sprojected image causing a “screen door” effect which thereby does notresult in a projected image that is robust. The screen door effect isalso known as fixed-pattern noise (FPN) and is a visual artifact of aplurality of fine lines that separate the projector's pixels, from thegaps between the mirror edges, which become visible in the projectedimage on the display screen.

Accordingly, what is needed is an apparatus and system for an opticallyreflective switching device in a display system which though reducesreliance on precise mirror arrangement and angular mechanicalperformances, improves resulting projected resolution with enhancedoperational reliability while being fixedly positioned in apredetermined state.

SUMMARY OF THE INVENTION

The present invention fulfills these needs and has been developed inresponse to the present state of the art, and in particular, in responseto the problems and needs in the art that have not yet been fully solvedby currently available security protocols and technologies.

An optically reflective switching device (ORSD) comprising an opticallyreflective layer having at least one electrochromic material, asubstrate, and an excitation means and controller, wherein said deviceis a capable of receiving light from a light source and thereafterreflecting said received light in direct response to a reflective statecondition of said optically reflective layer, is provided.

An array of a plurality optically reflective switching devices (ORSDs)having an optically reflective layer having at least one electrochromicmaterial, a substrate, and an associated excitation means andcontroller, wherein each of said devices is a capable of receiving lightfrom a light source and thereafter reflecting said received light indirect response to a reflective state condition of said opticallyreflective layer, is also provided.

A display system comprising a light source, a plurality of opticallyreflective switching devices each having an optically reflective layerin contact with a substrate, a circuit means and power source,controller logic, a projection means, and a display means, wherein eachof said plurality of devices is a capable of receiving light from saidlight source and thereafter reflecting said received light in directresponse to a reflective state condition of said each device.

The term “optically reflective switching device” is used in embodimentdescriptions interchangeably with the term “device” intentionally.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a pictorial representation of a mirror in a typical mirrorarray on a DMD.

FIG. 2 is a pictorial representation of a larger portion of the mirrorarray of FIG. 1.

FIG. 3 represents a pictorial representation of the underside of amirror having a diagonal hinge.

FIG. 4 is a cut-away pictorial representation of a mirror on a chip.

FIG. 5 represents a schematic of a typical DLP system.

FIG. 6 is a pictorial representation of a traditional projection DLPdisplay system.

FIG. 7 is a pictorial representation of a typical mirror undersidehaving two supports and two electrodes.

FIG. 8A is a pictorial representation of an optically reflectiveswitching device in accordance with one embodiment of the presentinvention.

FIG. 8B is a pictorial representation of a face side of a device havingan electrochromic composition layer in a typical array of the presentinvention.

FIG. 9 is a pictorial representation of an optically reflectiveswitching device in an active reflective mode in accordance with oneembodiment of the present invention.

FIG. 10 is a pictorial representation of an optically reflectiveswitching device in an active non-reflective mode in accordance with oneembodiment of the present invention.

FIG. 11 is a logical schematic of an optically reflective switchingdevice in a display system in accordance with one embodiment of thepresent invention.

FIG. 12 is an operational flow of a light path for an opticallyreflective switching device in a display system in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

The present invention generally relates to the field of high resolutiondisplay devices and systems. The following description is presented toenable one of ordinary skill in the art to make and use the inventionand is provided in the context of a patent application and itsrequirements. Various modifications to the preferred embodiments and thegeneric principles and features described herein will be readilyapparent to those skilled in the art. Thus, the present invention is notintended to be limited to the embodiments shown, but is to be accordedthe widest scope consistent with the principles and features describedherein.

FIG. 8A is a pictorial representation of an optically reflectiveswitching device 800 in accordance with one embodiment of the presentinvention. From FIG. 8A, an optically reflective layer 810 having anelectrical association as one of an electric field or a current chargeis in contact with a substrate layer 820. The substrate layer ispositioned above at least one support, not shown, and two electrodes 830and 840 are optionally shown with associated circuitry 860, 850 forreceiving current or commands from a power modulator, printed circuitboard (PCB), power source or software, not shown. An electric current,electric field signal or power source 870 is preferably available tosupply current or electric field proximate to the device 800 to affectthe reflective properties of the optically reflective layer 810.

Preferably the optically reflective layer 810 is comprised of acomposition inclusive of one or more materials capable of reversingtheir reflectivity state when exposed to an electric field or chargecurrent. For instance, electrochromic materials are examples ofmaterials which may appear transparent (i.e., uncolored) when exposed toan electric field or source, and may act as a mirror (i.e. reflective)when they are not exposed to an electric field or source, or vice versa.An example of an electrochromic material is polyaniline which can beformed by electrochemical or chemical oxidation of aniline and used in afilm of polyaniline on an electrode. Additional examples include but arenot limited to viologens, and polyoxotungstates.

An electrochromic optically reflective layer of the present invention,in a preferred embodiment, may also include a Nickel Magnesium (Ni—Mg)composition in various forms such as a film, whereupon the introductionof an electric current or electric field, a metal-to semiconductortransition takes place, and the film which is otherwise reflective thenbecomes transparent.

In a further preferred embodiment, the optically reflective layerincludes one or more transition metals in combination with Mg whichthereby form a layer composition inclusive of but not limited to metals,alloys, hydrides or mixtures of metals, alloys and/or hydrides. Examplesof the transition metals usable to create (via one of bonding, mixing,alloying or dissolving with Mg) a layer composition, include Sc, Ti, V,Cr, Mn, Fe, Co, Ni, Cu, Zn, Y Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La,Hf, Ta, W, Re, Os, Ir, Pt, Au and Hg. When deposited as a film, forexample, the layer composition appears mirror-like prior to anapplication of electric field or charge current.

In a preferred embodiment the optically reflective layer having anelectrochromic layer composition and is a film which is one of beinglaminated, electrochemically deposited, grown on, or otherwise incontact with the substrate, and is exposed to electric fields orcurrents by the presence of electrodes or power/electric sources (i.e.,870) at predetermined locations.

For example, in certain aspects of various preferred embodiments of thepresent invention, electrodes may reside: a) between a laminatedoptically reflective layer and the substrate; b) under the substrate infilm or circuitry; c) in one or more supports of the device; d) in or ona hinge under the substrate; or e) in various other configurations asmay be readily envisioned by one of ordinary skill so as to permit theelectric field or the charge current to be in reasonable proximity to orconnectivity with the optically reflective film layer.

In a preferred embodiment, advantageously, when one or more of theelectrodes associated with a particular device of the present inventionare active, an electric field is created and the transparency of theoptically reflective layer is affected to range from a reflective stateto one of a transparent state in relation to the electric field present.

In another preferred embodiment, advantageously, when a power source orexcitation means (i.e., 870) of the present invention is active, anelectric field is created and the transparency of the opticallyreflective layer is affected to range from a reflective state to one ofa transparent state in relation to the electric field present. Where theelectric source is of a sufficient amount, the optically reflectivelayer is transparent (i.e. colorless or uncolored) and no light of anincoming source is reflected. Where the electric source is not of asufficient amount, the optically reflective layer is reflective (i.e.colored) and light of an incoming source is reflected.

In the operation of a preferred embodiment, since a state change to anoptically reflective layer requires an electric field or a currentcharge, the associated state or color change of an optically reflectivelayer is affected only when such is applied.

FIG. 8B is a pictorial representation of a face side 890 of a devicehaving an electrochromic composition layer in a typical array 880 of thepresent invention. The face side 890 of a device in the array 880 hasminute spacing 899 between the each device of the array. In a preferredembodiment, the spacing between each device on an array is envisioned tobe on the order of less than 20 micrometers.

FIG. 9 is a pictorial representation of an optically reflectiveswitching device 900 in an active reflective mode in accordance with oneembodiment of the present invention. From FIG. 9, an opticallyreflective layer 910 having an electrochromic layer composition is incontact with a substrate layer 920. The substrate layer is positionedabove at least one support, not shown, and two electrodes 930 and 940are shown. Electrodes 930 and 940 are in electrical communication withassociated circuitry 960, 950, are for receiving current or commandsfrom a power modulator, or software, not shown, and thereby provide anelectric field, at 970 and 980, or electric source (not shown) to theoptically reflective layer 910 affecting its reflectivity.

From FIG. 9, the incoming light source 915 is transmitted through acolor wheel 917 and the resulting colored light is partly reflected asreflected light at 916 from the optically reflective layer 910 inrelation to the electric fields 970, 980 which are generating anelectric field or current, thereby causing the optically reflectivelayer 910 to not be wholly reflective and or of a particular color.Preferably the color wheel 917 is in electrical communication with acontroller, not shown, to associate a predetermined color of the colorwheel with the incoming light source 915 so as to shine a particularcolored light at 918 on a device having a reflective layer 910 at apredetermined time.

FIG. 10 is a pictorial representation of an optically reflectiveswitching device 1000 in an active non-reflective mode in accordancewith one embodiment of the present invention. From FIG. 10, an opticallyreflective layer 1010 having an electrochromic layer composition is incontact with a substrate layer 1020 having circuitry and a power source1030 to the circuitry. The power source supplies electric current to thelayer 1010 via the circuitry of the substrate 1020. From FIG. 10, theincoming light source 1015 is not reflected at 1016 from the opticallyreflective layer 1010 in relation to the electric fields generated asthe layer 1010 is transparent.

In a preferred embodiment, a color wheel, not shown, is in electricalcommunication with a controller, not shown, to associate a predeterminedcolor of the color wheel with the incoming light source 1015 so as toshine a particular colored light on a device having a reflective layer1010 at a predetermined time.

FIG. 11 is a logical schematic of an optically reflective switchingdevice in a display system 1100 in accordance with one embodiment of thepresent invention. A light source 1110, a color wheel 1120, an opticallyreflective layer on a substrate having a circuit and power source 1130,processor logic (such as but not limited a command logic) 1140, and aprojection means such as a projection lens 1150, is set forth. From FIG.11, as the light source of 1110 passes through the color wheel 1120, acolored light is reflected onto the optically reflective layer of thedevice and the layer is affected in a predetermined manner by anassociated power source and circuitry thereto. In response to the powersource controlled by the logic 1140, the optically reflective layer 1130is either transparent or reflective, as in the predetermined manner, anda resulting colored light is either reflected from the layer 1130 andthen projected through the lens 1150 for viewing or is not reflected at1130. In the system of the present invention, the optically reflectivelayer and associated substrate is fixedly positioned in an array of aplurality of devices, each having optically reflective layers,substrates, and associated logic.

FIG. 12 is an operational flow of a light path for an opticallyreflective switching device in a display system 1200 in accordance withone embodiment of the present invention. From FIG. 12, the systemcomprises a light source 1210, a color wheel 1215, and an array ofdevices having electrochromic layer compositions 1220, each havinglogic, not shown, a projection means 1230 and a display means 1240. Thelight source 1211 of 1210 enters the color wheel 1215 and is emitted at1212 after passing though the color wheel 1215 as colored light.Preferably the color of the color wheel is determined by a controllerassociated with the color wheel. The light emitted from the color wheelat 1211 is then received by a device of the present invention which ispart of the array of devices 1220. The device receives the colored lightof 1212 and then acts to either reflect or not reflect the colored lightof 1212 in relation to the transparency of the optically reflectivelayer of the device. Where the optically reflective layer of the deviceis reflective (i.e., mirror state) then the received color light isreflected at 1214 to a projection lens at 1230. The projection lens 1230then passes the received reflected light of 1214 to a display screen1240 for viewing. Where the optically reflective layer of the device isnot reflective (i.e., transparent state), due to the electrical signalsaffecting the electrochromic properties of the optically reflectivelayer of the device, then the received color light at 1212 is notreflected and a black color appears in a display screen 1240 at alocation in relation to the device's pixel display location on thescreen 1240. This process repeats itself thousands of times per secondper device by the application of a predetermined electric current orelectric field in relation to each device in an array of a displaysystem of the present invention.

A display system of the present invention will vary in the number ofdevices in an array, where each device has an electrochromic layercomposition, substrate and associated electrical source, in view of theresolution sought for a particular system. For instance, the number ofdevices in an array, and the corresponding size of the resulting array,directly affect and correspond to the resolution of the projected image,such that resolution characteristics are continually increased withlarger arrays.

It is envisioned that devices of the present invention may includesoftware, circuitry, firmware, electronics, components on circuitsboards, chips on flex, fixedly mounted DMDs, and the like, whereapplications of the present invention may be used in any display system,device or display means requiring reflection of sourced light and pixeldisplay. Further, many of the associated controller, logic and signalsmay be performed by a computer program product stored on a computerusable medium comprising one or more of the embodiments herein.

As used herein for the purposes of the present invention, the terms“electric field,” “electric current,” “charge current,” “electriccharge,” “power source,” “excitation means” and “current source” areintended to be used interchangeably and to have a common interpretation.

As used herein for the purposes of the present invention, the term“optical switching device” is the intended to be a general term having abroad meaning in use whereby it may be described in part, but notlimited to, as being a mirror, an electronically-controlled switch, anelectrically-charged optical switch or any other switching devices thathas its ability to switch “ON” or “OFF” determined by an electronic orelectrical impulse or signal.

Any theory, mechanism of operation, proof, or finding stated herein ismeant to further enhance understanding of the present invention and isnot intended to make the present invention in any way dependent uponsuch theory, mechanism of operation, proof, or finding. It should beunderstood that while the use of the word preferable, preferably orpreferred in the description above indicates that the feature sodescribed may be more desirable, it nonetheless may not be necessary andembodiments lacking the same may be contemplated as within the scope ofthe invention, that scope being defined by the claims that follow.

In reading the claims it is intended that when words such as “a,” “an,”“at least one,” “at least a portion” are used there is no intention tolimit the claim to only one item unless specifically stated to thecontrary in the claim. Further, when the language “at least a portion”and/or “a portion” is used the item may include a portion and/or theentire item unless specifically stated to the contrary. While theinvention has been illustrated and described in detail in the drawingsand foregoing description, the same is to be considered as illustrativeand not restrictive in character, it being understood that only theselected embodiments have been shown and described and that all changes,modifications and equivalents that come within the spirit of theinvention as defined herein or by any of the following claims aredesired to be protected.

What is claimed is:
 1. A display system comprising: a light source;array of a plurality optically reflective switching devices (ORSDs)having an optically reflective layer having at least one electrochromicmaterial, a substrate, and an associated excitation means andcontroller, and a computer program product stored on a computer usablemedium comprising computer readable program means for causing saidcomputer to control an execution of an application; the computer programproduct including program instructions for controlling said excitationmeans to electrically excite said layer of each device to a first stateof excitation or to a second state of excitation; a circuit means andpower source; one or more controller logic; a color wheel means; aprojection means; and a display means; wherein each of said plurality ofdevices is a capable of receiving light from said light source andthereafter reflecting said received light in direct response to areflective state condition of said each device, wherein a transparencyof the optically reflective layer is affected to range from thereflective state condition to a transparent state condition in relationto a present electric field.
 2. The system of claim 1, wherein saidlayer of each device includes a transition metal of at least one of Ti,V, Cr, Mn, Fe, Go, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf,Ta, W, Re, Os, Ir, Pt, Au and Hg, and said layer of each device is inone of a first reflective state or a second reflective state in relationto said one or more controller logic.
 3. The system of claim 1, whereinin a transparent state condition, receiving light from said light sourceand thereafter passing said received light through without reflection indirect response to the transparent state condition of said each device.4. The system of claim 1, wherein the array of a plurality of ORSDs isimplemented with minute spacing between each device of the array.
 5. Thesystem of claim 4, wherein the minute spacing is on the order of lessthan 20 micrometers.